Candle Under Water

REQUIREMENTS:-

WHAT TO DO:-

Pour some water into the saucer and then add a few drops of colour to it and mix well. Now, light up the candle and place it in the middle of the saucer and then cover it up with the cup.

WHAT HAPPENS:-

With the flame still burning inside the cup, some of the water starts collecting inside the glass, coming in from outside, and when the flame goes off there is a much bigger gush of water into the glass.

WHY THIS HAPPENS:-

The flame uses up the oxygen in the cup, creating low pressure. Atmospheric pressure then tries to force its way in. Becuase the water at the base of the cup has create an airtight seal, the pressure difference between the inside and outside of the cup causes the water to rise till the pressure (inside the cup) is equal to the pressure outside.TRY THIS:-
Try this experiment with different sizes of candles to see if more water is absorbed into the glass.